// Package mock provides a fake garmin.Client for tests and frontend/dev
// work without a live Garmin account or the wrapper subprocess.
package mock

import (
	"context"
	"time"

	"geniusrun/backend/internal/garmin"
)

// Client is a fake garmin.Client returning data supplied by the test/caller.
type Client struct {
	AuthResults []garmin.AuthResult // consumed in order by Authenticate/CompleteMFA calls
	Activities  []garmin.Activity
	Splits      map[int64]garmin.ActivitySplits
	Details     map[int64]garmin.ActivityDetails
	Workouts    map[int64]garmin.Workout
	// WorkoutErrByID, if set for a given workout ID, makes GetWorkoutByID
	// return that error for that ID specifically -- independent of the
	// all-calls-fail Err field below -- so a test can simulate one
	// activity's workout fetch failing while others in the same batch
	// succeed.
	WorkoutErrByID map[int64]error
	// Delay, if set, is slept (ctx-cancellable) at the start of every
	// GetActivities call -- lets a test give sync.Service's discovering
	// phase (backfillCore/incrementalSyncCore) real wall-clock duration, so
	// a concurrent goroutine can observe Progress() mid-flight instead of
	// the call returning instantly.
	Delay              time.Duration
	Err                error // if set, every call returns this error
	authResultCursor   int
	ClosedCalled       bool
	GetActivitiesCalls int
	AuthenticateCalls  int
	LastEmail          string
	LastPassword       string
}

var _ garmin.Client = (*Client)(nil)

func (c *Client) nextAuthResult() garmin.AuthResult {
	if c.authResultCursor >= len(c.AuthResults) {
		return garmin.AuthResult{Status: garmin.AuthSuccess, Message: "Authenticated successfully."}
	}
	r := c.AuthResults[c.authResultCursor]
	c.authResultCursor++
	return r
}

func (c *Client) Authenticate(ctx context.Context) (garmin.AuthResult, error) {
	c.AuthenticateCalls++
	if c.Err != nil {
		return garmin.AuthResult{}, c.Err
	}
	return c.nextAuthResult(), nil
}

func (c *Client) CompleteMFA(ctx context.Context, code string) (garmin.AuthResult, error) {
	if c.Err != nil {
		return garmin.AuthResult{}, c.Err
	}
	return c.nextAuthResult(), nil
}

func (c *Client) GetActivities(ctx context.Context, startDate, endDate string, limit int) ([]garmin.Activity, error) {
	c.GetActivitiesCalls++
	if c.Delay > 0 {
		select {
		case <-ctx.Done():
			return nil, ctx.Err()
		case <-time.After(c.Delay):
		}
	}
	if c.Err != nil {
		return nil, c.Err
	}
	if limit > 0 && limit < len(c.Activities) {
		return c.Activities[:limit], nil
	}
	return c.Activities, nil
}

func (c *Client) GetActivitySplits(ctx context.Context, activityID int64) (garmin.ActivitySplits, error) {
	if c.Err != nil {
		return garmin.ActivitySplits{}, c.Err
	}
	return c.Splits[activityID], nil
}

func (c *Client) GetActivityDetails(ctx context.Context, activityID int64) (garmin.ActivityDetails, error) {
	if c.Err != nil {
		return garmin.ActivityDetails{}, c.Err
	}
	return c.Details[activityID], nil
}

func (c *Client) GetWorkoutByID(ctx context.Context, workoutID int64) (garmin.Workout, error) {
	if c.Err != nil {
		return garmin.Workout{}, c.Err
	}
	if err, ok := c.WorkoutErrByID[workoutID]; ok {
		return garmin.Workout{}, err
	}
	return c.Workouts[workoutID], nil
}

func (c *Client) UpdateCredentials(email, password string) {
	c.LastEmail = email
	c.LastPassword = password
}

func (c *Client) Close() error {
	c.ClosedCalled = true
	return nil
}